The present invention relates generally to space technology, and, more specifically, to launching spacecraft into earth orbit.
Since the dawn of the space age spacecraft have been launched into outer space in orbit around the earth using rocket propulsion. The majority of weight of the spacecraft is found in the main rocket motor(s) and the required fuel and oxidizer therefor, leaving little weight for the remaining spacecraft itself which reaches earth's orbit. Spacecraft may either be manned or unmanned, and in either case may be used for placing payloads, such as satellites, for example, in earth's orbit.
The cost to launch payloads into outer space around the earth is about $10,000 per kilogram in Low Earth Orbit (LEO). The cost for Geosynchronous Earth Orbit (GEO) and planetary exploration is much greater. Paradoxically, the energy cost to reach space is very small for objects directly accelerated to orbital velocities. The energy to place a kilogram in LEO then costs only 50 cents at 5 cents per kilowatt hour, a factor of about 10,000 smaller than the present cost with rockets.
This high cost results from the inherent limitations of rockets, with their payload fraction being only about 1%, and they are complex and very expensive for both expendable and reusable versions, such as the shuttle. The development of improved reusable single stage to orbit (SSTO) spacecraft, or high Mach air breathing space planes (NASP), could cut launch costs somewhat, but they still will be high, about $1000/kg or more.
Accordingly, it is desired to provide an improved method and apparatus for launching spacecraft into outer space, including earth's orbit, eliminating or reducing the need for rocket propulsion.